The invention relates to a grinding disk in particular for rotary fine machining of surfaces. The grinding disk comprises a support plate having a top-side drive connector for connecting the grinding disk to a rotating drive machine. The support plate is provided with an elastically deformable cushion that is at the bottom side covered with a working medium or with an adhesive coating for releasable attachment of a working medium disk. The support plate is provided with a cover that is positioned at an axial intermediate spacing to the support plate.
Such a grinding disk is disclosed, for example, in German utility model 20 2009 000 880 U1. Grinding disks of this kind are typically attached to rotating driving machines such as power drills or grinding machines in order to support a working medium disk that is to be moved in rotation with the grinding disk concentrically or even eccentrically.
In principle, the working medium disk is embodied as a wear part with material expenditure as little as possible and therefore is provided with little inherent stiffness. The support of the working medium disk by the grinding disk provides generally a yielding action for adaptation to the surfaces to be machined that is generally provided as a coating in the form of an elastically deformable cushion. However, as a whole a stiff configuration of the grinding disk is required in order to be able to perform the grinding or polishing movements in a controlled fashion and, primarily, to prevent in case of great work loads deformations that could cause the grinding disk to contact the driving machine.
The stiffness requirement is however contrary to the need for a lightweight construction that facilitates handling as the working movements are carried out and that, in case of eccentric grinding machines, complies with weight limits which should not be exceeded with respect to a mass compensation for eccentric and vibration systems.
Another configuration of a grinding disk is disclosed in DE 10 2010 012 007 A1 according to which the manufacture of suction passages in the grinding disk is to be simplified. This configuration has no cover and provides, between a support plate provided with the top-side drive connector and an elastically deformable cushion, a hollow air guiding part of plastic material that is attached underneath the support plate before the cushion is applied by foaming. In this way, the deformable cushion and the support plate are immediately connected to each other only along the rim and the static and dynamic work loads are primarily transmitted through the air guiding part. This results in a reduced stiffness and/or a massive and heavy construction.
It is the object of the present invention to provide a grinding disk that is developed further, on the one hand, to have a high inherent stiffness and, on the other hand, is provided with a reduced weight but is conventionally robust and can be used easily and also can be manufactured by mass production.